[PATCH] D36596: [InstCombine] Add a flag to disable LowerDbgDeclare

[Reid Kleckner via Phabricator via llvm-commits]

rnk added a comment.

In https://reviews.llvm.org/D36596#864089, @aprantl wrote:

> Ok. I think there should be a PR to revert this change that is blocked on PR34136. The description of the option should explicitly spell out a big warning that this will introduce false positives and that it is experimental/temporary only. We should aim to get this reverted as soon as possible.


Are you sure we need a new PR? To fix PR34136, we effectively need to enable the new behavior all the time: stop converting dbg.declare or dbg.addr to dbg.value in instcombine. We just can't do that today because we don't have the infrastructure to fix all the inaccurate debug info that such a change would create. Once we have dbg.addr, we can fix DSE to avoid inaccuracies, but only if we leave dbg.addr alone in instcombine.

Anyway, uploading a new patch shortly with a FIXME comment describing what the flag does and when it can be removed.


https://reviews.llvm.org/D36596